DON'T TRUST SAM WEISS
Sam Weiss is dude from the bowling alley that Olivia has visited several times for advice, and was also the secret glyph clue for "Over There, Part 2".
Why would Sam Weiss be someone not to be trusted? Who left this message in the alternate universe? Do they mean the Sam Weiss from our universe, of the one from "over there"?
* Thanks to Andrew for decoding this!